A base station is an installed wireless communications station which acts as a controller for a communication system. It will be appreciated that it acts as a service provider to the subscribers and the service can be any kind of data transmission. It will be appreciated that a base station can also be used as a repeater for improving a communication link.
Examples of base stations are, but are not limited to, a cellular mobile tower, a radio station tower, a data transmission satellite, etc. A base station can be a wireless signal transmitter or a transceiver.
A subscriber of the wireless data communication service is typically referred to as a user.
Examples of users are, but are not limited to, a cellular phone subscriber, a radio receiver, a satellite signal receiver station on earth or in space, etc. A user can be a wireless signal receiver or a transceiver.
As known to the skilled addressee, a cognitive radio is an intelligent radio that can be programmed and configured dynamically. Consequently, such radio changes its transmission or reception parameters in order to allow more concurrent wireless communication in a given spectrum band at a given location.
The Cognitive Radio System terminology states a receiver as the user and a transmitter as the base station (BS).
The frequency band over which the cognitive radio (CR) system is deployed is called a cognitive radio (CR) band.
A licensed user in the cognitive radio system is known as the primary user (PU) and a user trying to communicate opportunistically on the licensed frequency band of the primary user is called the secondary user (SU).
The skilled addressee will appreciate that the three kinds of participants involved in a cognitive radio system are the primary user(s), the secondary user(s) and the base station(s) that are not licensed to transmit in the cognitive radio band. The term ‘base station’ will be used in this document to refer to this second type of base station, the “cognitive radio.” It is responsible for sensing the environment around it and adapting to it accordingly.
There are three major cognitive radio paradigms and they are known as underlay, interweave and overlay.
In the underlay technique, the cognitive radio transmits along with the licensed base station, and it is constrained to cause minimal interference to the primary user(s). Thus the cognitive radio does not have to wait for the licensed base station to stop its transmission to use its frequency band in underlay. Unfortunately, this technique is computationally complex and hard to implement optimally.
A simple example of an underlay cognitive radio system is shown in FIG. 1.
In the interweave paradigm, the cognitive radio finds and exploits spectral holes to transmit its own data. For example, it looks for the frequency bracket or the time frame where the licensed base station is not transmitting and then opportunistically transmits on that frequency or time to avoid interference.
The third paradigm, known as the overlay, is used for overhearing and enhancing the transmission of the licensed base station.
There is a need for a method for optimizing asset allocation in an “underlay” cognitive radio configuration.
Features of the invention will be apparent from review of the disclosure, drawings and description of the invention below.